Patent Literature 1 discloses a two-dimensional photonic crystal vertical cavity surface emitting laser. Its lattice structure is a square lattice or orthogonal lattice. The lattice structure has translational symmetry. The shape of lattice points is triangular.
Patent Literature 2 discloses a surface emitting laser. The surface emitting laser has a laminated body, a first electrode, and a second electrode. The laminated body has an active layer and a two-dimensional photonic crystal. The laminated body lies between the first electrode and the second electrode. The first electrode has an annular shape. The two-dimensional photonic crystal lases to emit a laser beam. The laser beam has an annular cross-sectional shape and is radially polarized.